diff --git a/libtransmission/bandwidth.c b/libtransmission/bandwidth.c
index 500d34bf6..01b7ad928 100644
--- a/libtransmission/bandwidth.c
+++ b/libtransmission/bandwidth.c
@@ -34,22 +34,32 @@
 static unsigned int
 getSpeed_Bps( const struct bratecontrol * r, unsigned int interval_msec, uint64_t now )
 {
-    uint64_t       bytes = 0;
-    const uint64_t cutoff = (now?now:tr_time_msec()) - interval_msec;
-    int            i = r->newest;
+    if( !now )
+        now = tr_time_msec();
 
-    for( ;; )
+    if( now != r->cache_time )
     {
-        if( r->transfers[i].date <= cutoff )
-            break;
+        int i = r->newest;
+        uint64_t bytes = 0;
+        const uint64_t cutoff = now - interval_msec;
+        struct bratecontrol * rvolatile = (struct bratecontrol*) r;
 
-        bytes += r->transfers[i].size;
+        for( ;; )
+        {
+            if( r->transfers[i].date <= cutoff )
+                break;
 
-        if( --i == -1 ) i = HISTORY_SIZE - 1; /* circular history */
-        if( i == r->newest ) break; /* we've come all the way around */
+            bytes += r->transfers[i].size;
+
+            if( --i == -1 ) i = HISTORY_SIZE - 1; /* circular history */
+            if( i == r->newest ) break; /* we've come all the way around */
+        }
+
+        rvolatile->cache_val = (unsigned int)(( bytes * 1000u ) / interval_msec);
+        rvolatile->cache_time = now;
     }
 
-    return (unsigned int)(( bytes * 1000u ) / interval_msec);
+    return r->cache_val;
 }
 
 static void
@@ -63,6 +73,9 @@ bytesUsed( const uint64_t now, struct bratecontrol * r, size_t size )
         r->transfers[r->newest].date = now;
         r->transfers[r->newest].size = size;
     }
+
+    /* invalidate cache_val*/
+    r->cache_time = 0;
 }
 
 /******
@@ -88,7 +101,7 @@ tr_bandwidthConstruct( tr_bandwidth * b, tr_session * session, tr_bandwidth * pa
 {
     b->session = session;
     b->children = TR_PTR_ARRAY_INIT;
-    b->magicNumber = MAGIC_NUMBER;
+    b->magicNumber = BANDWIDTH_MAGIC_NUMBER;
     b->band[TR_UP].honorParentLimits = TRUE;
     b->band[TR_DOWN].honorParentLimits = TRUE;
     tr_bandwidthSetParent( b, parent );
@@ -215,7 +228,7 @@ phaseOne( tr_ptrArray * peerArray, tr_direction dir )
     i = n ? tr_cryptoWeakRandInt( n ) : 0; /* pick a random starting point */
     while( n > 1 )
     {
-        const size_t increment = 256;//1024;
+        const size_t increment = 512;//1024;
         const int bytesUsed = tr_peerIoFlush( peers[i], dir, increment );
 
         dbgmsg( "peer #%d of %d used %d bytes in this pass", i, n, bytesUsed );
@@ -319,20 +332,20 @@ bandwidthClamp( const tr_bandwidth  * b,
     {
         if( b->band[dir].isLimited )
         {
-            double current = tr_bandwidthGetRawSpeed_Bps( b, now, TR_DOWN );
-            double desired = tr_bandwidthGetDesiredSpeed_Bps( b, TR_DOWN );
-            double r = desired > 0.001 ? current / desired : 0;
-            size_t i;
-
             byteCount = MIN( byteCount, b->band[dir].bytesLeft );
 
-                 if( r > 1.0 ) i = 0;
-            else if( r > 0.9 ) i = byteCount * 0.9;
-            else if( r > 0.8 ) i = byteCount * 0.8;
-            else               i = byteCount;
+            /* if we're getting close to exceeding the speed limit,
+             * clamp down harder on the bytes available */
+            if( byteCount > 0 )
+            {
+                double current = tr_bandwidthGetRawSpeed_Bps( b, now, TR_DOWN );
+                double desired = tr_bandwidthGetDesiredSpeed_Bps( b, TR_DOWN );
+                double r = desired >= 1 ? current / desired : 0;
 
-            //fprintf( stderr, "--> %.4f  (%f... %f) [%zu --> %zu]\n", r, current, desired, byteCount, i );
-            byteCount = i;
+                     if( r > 1.0 ) byteCount = 0;
+                else if( r > 0.9 ) byteCount *= 0.8;
+                else if( r > 0.8 ) byteCount *= 0.9;
+            }
         }
 
         if( b->parent && b->band[dir].honorParentLimits && ( byteCount > 0 ) )
diff --git a/libtransmission/bandwidth.h b/libtransmission/bandwidth.h
index 151f0d8e7..471c5ec2a 100644
--- a/libtransmission/bandwidth.h
+++ b/libtransmission/bandwidth.h
@@ -38,7 +38,7 @@ enum
     INTERVAL_MSEC = HISTORY_MSEC,
     GRANULARITY_MSEC = 200,
     HISTORY_SIZE = ( INTERVAL_MSEC / GRANULARITY_MSEC ),
-    MAGIC_NUMBER = 43143
+    BANDWIDTH_MAGIC_NUMBER = 43143
 };
 
 /* these are PRIVATE IMPLEMENTATION details that should not be touched.
@@ -47,6 +47,8 @@ struct bratecontrol
 {
     int newest;
     struct { uint64_t date, size; } transfers[HISTORY_SIZE];
+    uint64_t cache_time;
+    unsigned int cache_val;
 };
 
 /* these are PRIVATE IMPLEMENTATION details that should not be touched.
@@ -141,7 +143,7 @@ static inline void tr_bandwidthFree( tr_bandwidth * bandwidth )
 /** @brief test to see if the pointer refers to a live bandwidth object */
 static inline tr_bool tr_isBandwidth( const tr_bandwidth  * b )
 {
-    return ( b != NULL ) && ( b->magicNumber == MAGIC_NUMBER );
+    return ( b != NULL ) && ( b->magicNumber == BANDWIDTH_MAGIC_NUMBER );
 }
 
 /******
diff --git a/libtransmission/peer-io.c b/libtransmission/peer-io.c
index 8a2ae57ec..b0dc39ece 100644
--- a/libtransmission/peer-io.c
+++ b/libtransmission/peer-io.c
@@ -39,8 +39,6 @@
 #include "utils.h"
 
 
-#define MAGIC_NUMBER 206745
-
 #ifdef WIN32
  #define EAGAIN       WSAEWOULDBLOCK
  #define EINTR        WSAEINTR
@@ -139,8 +137,6 @@ canReadWrapper( tr_peerIo * io )
 
     dbgmsg( io, "canRead" );
 
-    assert( tr_isPeerIo( io ) );
-    assert( tr_isSession( io->session ) );
     tr_peerIoRef( io );
 
     session = io->session;
@@ -160,8 +156,6 @@ canReadWrapper( tr_peerIo * io )
             const size_t used = oldLen - evbuffer_get_length( io->inbuf );
             const unsigned int overhead = guessPacketOverhead( used );
 
-            assert( tr_isPeerIo( io ) );
-
             if( piece || (piece!=used) )
             {
                 if( piece )
@@ -197,20 +191,9 @@ canReadWrapper( tr_peerIo * io )
         tr_sessionUnlock( session );
     }
 
-    assert( tr_isPeerIo( io ) );
     tr_peerIoUnref( io );
 }
 
-tr_bool
-tr_isPeerIo( const tr_peerIo * io )
-{
-    return ( io != NULL )
-        && ( io->magicNumber == MAGIC_NUMBER )
-        && ( io->refCount >= 0 )
-        && ( tr_isBandwidth( &io->bandwidth ) )
-        && ( tr_isAddress( &io->addr ) );
-}
-
 static void
 event_read_cb( int fd, short event UNUSED, void * vio )
 {
@@ -564,7 +547,7 @@ tr_peerIoNew( tr_session       * session,
     }
 
     io = tr_new0( tr_peerIo, 1 );
-    io->magicNumber = MAGIC_NUMBER;
+    io->magicNumber = PEER_IO_MAGIC_NUMBER;
     io->refCount = 1;
     io->crypto = tr_cryptoNew( torrentHash, isIncoming );
     io->session = session;
diff --git a/libtransmission/peer-io.h b/libtransmission/peer-io.h
index e764cf19f..df50c425d 100644
--- a/libtransmission/peer-io.h
+++ b/libtransmission/peer-io.h
@@ -144,8 +144,17 @@ void tr_peerIoUnrefImpl         ( const char              * file,
 
 #define tr_peerIoUnref(io) tr_peerIoUnrefImpl( __FILE__, __LINE__, (io) );
 
-tr_bool     tr_isPeerIo         ( const tr_peerIo         * io );
+#define PEER_IO_MAGIC_NUMBER 206745
 
+static inline tr_bool
+tr_isPeerIo( const tr_peerIo * io )
+{
+    return ( io != NULL )
+        && ( io->magicNumber == PEER_IO_MAGIC_NUMBER )
+        && ( io->refCount >= 0 )
+        && ( tr_isBandwidth( &io->bandwidth ) )
+        && ( tr_isAddress( &io->addr ) );
+}
 
 /**
 ***
@@ -355,17 +364,12 @@ void      tr_peerIoBandwidthUsed( tr_peerIo           * io,
 static inline tr_bool
 tr_peerIoHasBandwidthLeft( const tr_peerIo * io, tr_direction dir )
 {
-    assert( tr_isPeerIo( io ) );
-
     return tr_bandwidthClamp( &io->bandwidth, dir, 1024 ) > 0;
 }
 
 static inline unsigned int
 tr_peerIoGetPieceSpeed_Bps( const tr_peerIo * io, uint64_t now, tr_direction dir )
 {
-    assert( tr_isPeerIo( io ) );
-    assert( tr_isDirection( dir ) );
-
     return tr_bandwidthGetPieceSpeed_Bps( &io->bandwidth, now, dir );
 }